Need help diagnosing weird sound on a POD tone.

Have you tried recording in different rooms? And did you try recording with the lights off?
 
Interesting.

I posted the patch I made, the one that I first noticed this noise on, on the L6 Support Forums. Someone w/ whom I was corresponding w/ tried it and got that same sound, only they said not a severely as I was getting it.

Perhaps I've found the L6 self-destruct patch? :D
 
have you tried other combinations of dual amp setups, or have you solo'd each amp in your current patch to see if one or the other causes the noise?

I was getting the sound regardless of what amps I was using, even on clean tones.

It appears that using two noise gates in each chain was exacerbating the problem, but I had to because just using one wasn't enough to quiet the hum.

Anyways, the background hum was acting up much less than usual today, and I was able to lose one of the gates. Doing so lessened the noise i was getting considerably, but it's still there though.
 
I live in India so I face power cuts sometimes.
The sound you're getting is the sound I get usually when the PC is running on the UPS. Try using a different USB cable and maybe a balanced guitar cable.